Performance Of Suspended Carriers Anaerobic Membrane Bioreactor For Brewery Wastewater Treatment

In this experiment,the polyethylene carriers was added to the anaerobic membrane bioreactor(An MBR)to construct a suspended carriers An MBR system to treat brewery wastewater.Under the condition of reaction temperature was 35±2°C and HRT was 48h,the effects of pollutant removal,microbial population structure and membrane fouling of suspended carriers An MBR system were studied.The following conclusions were obtained:(1)In the start-up phase,the organic loading rate(OLR)was gradually increased from 0.48 kg COD/(m~3·d)to 2.12 kg COD/(m~3·d),the start-up of An MBR lasted 16 days.After successful start-up,the COD removal rate reached 96.0%.The p H,alkalinity(ALK)and volatile fatty acid(VFA)in the reactor were normal during the startup process.suspended carriers was added to the anaerobic tank to hanging film.After 40d,the biomass attached to the suspended carriers became stable,reaching about 117.59mg/g.(2)In the stable operational phase,compared with the suspended carriers unfilled An MBR when the influent COD concentration was 3000?5000 mg/L,The COD removal rate of suspended carriers An MBR increased by 1.1%to 97.5%;the average daily gas production increased by 1.57 L/d to 19.57 L/d.The concentration of ammonia nitrogen and phosphate in the effluent of the reactor was higher than that in the influent water in the stable operational phase.this indicated that the suspended carriers An MBR constructed in this experiment does not have the ability to remove ammonia nitrogen and phosphate,it is necessary to remove nitrogen and phosphorus from the effluent of the reactor.(3)In the load shock stage,the reactor influent COD load was increased to 1.6times,2.1 times and 4.1 times of the stable operation period for the load shock test.after1.6 times and 2.1 times load shock for 12 h,the COD removal rate of the system did not fluctuate greatly,maintaining 98.6%and 97.9%respectively;after 4.1 times load shock 12 h,the system COD The removal rate decreased to 92.8%,the effluent COD concentration returned to normal level 24 hours after the end of the load shock There was a good adaptability and recovery ability for short time shock loads for this suspended carriers An MBR.(4)The results of microbial population structure analysis showed that the microbial community structure diversity of the suspended carriers An MBR system was rich.The main types of microorganisms include the euryarchaeota,chloroflexi,croteobacteria,cirmicutes,cloacimonetes,chermotogae and bacteroidetes.Methanogens are the dominant species in the suspended carriers An MBR system.The proportion of methanogens in mixed sludge,biofilm of suspended carriers and the sludge in the cake layer was 17.31%,26.62%and 16.63%,respectively.The proportion of methanobacterium sp.and methanothrix sp.was relatively high,accounting for10.07%?21.85%and 2.26%?5.91%,respectively.(5)The study of membrane fouling characteristics showed that compared with the suspended carriers unfilled An MBR,the total filtration resistance(R_t),the cake layer filtration resistance(R_c)and R_c/R_t of the suspended carriers An MBR were lower,and the SMP and EPS contents of the mixture were decreased.20.5%and 29.4%,the cake layer EPS decreased by 20.5%,the membrane fouling rate slowed down;when the mixture reflux ratio increased from 50%to 400%,R_t and R_c increased,the membrane fouling rate slowed down;hydraulic backwash can effectively control the initial membrane fouling.Increasing the hydraulic backwash frequency can reduce R_t and R_c,slow down the membrane flux decline rate,and prolong the chemical cleaning cycle of membrane modules.(6)The fluorescent substances in the mixed liquid EPS and cake layer EPS of the suspended carriers An MBR system were mainly aromatic proteins and tryptophan proteins.Adding suspended carriers was beneficial to reduce the content of aromatic protein in the mixture liquid EPS.The accumulation of tryptopha proteins in the cake layer EPS was an important factor that affecting membrane fouling.FTIR analysis shows that protein and polysaccharide were the main organic components in the sludge of mixed liquid,and it also an important component of membrane surface pollutants.